Zelda games don't really sell as big as their reputations, so 4 million lifetime will be difficult

It will sell 83 copies. No more, no less. Lock me in on that answer.

Lifetime will most likely be over 10m across the Switch and Wii U imo.

Across both versions:

FW: 1.8M
LT: 7M

I think until now we had at least 5 threads like this one, in any case i predict around 7-8m LT sales.

I'll say 5 million. It'll get a hardware boost from being early in the Switch cycle, buuuuuuut the fringe fans who are Ocarina of Time lovers IMO don't like cell shaded Zelda.

Of actual "Zelda" hardcore faithful the fanbase is smaller than people think it is. What Ocarina of Time/Twilight Princess managed to do was get more fringe fans because they were considered the standard epic adventure games of their time.

Cell-shaded Zelda simply sells less than Zelda games w/a grown Link + realistic graphics. Ocarina of Time and Twilight Princess wipe the floor with Wind Waker and Skyward Sword.

OoT and TP were able to break out and sell to more than just Zelda fans. 

Any other games FW and LT we should take consideration of?

First week 1.5m
Lifetime 8.5m

Twilight Princess only sold around 6 million on Wii's 100 million installbase, so I don't think it matters how much a console sells, it's going to stay in that 5-6 million range.

What if the reviews are poor or there is some major failing of the wii u version compared to Switch? Too many variables.

I'll say 750,000 LT for wii u and 3.5-4.5 million LT on Switch and increase those numbers by 1-2 million if it gets bundled with Switch at some point.